All-Si photodetector for telecommunication wavelength based on subwavelength grating structure and critical coupling

Abstract

We propose an efficient planar all-Si internal photoemission photodetector operating at the telecommunication wavelength of 1550 nm and numerically investigate its optical and electrical properties. The proposed polarization-sensitive detector is composed of an appropriately engineered subwavelength grating structure topped with a silicide layer of nanometers thickness as an absorbing material. It is shown that a nearly-perfect light absorption is possible for the thin silicide layer by its integration to the grating resonator. The absorption is shown to be maximized when the critical coupling condition is satisfied. Simulations show that the external quantum efficiency of the proposed photodetector with a 2-nm-thick PtSi absorbing layer at the center wavelength of 1550 nm can reach up to ∼60%.

All-Si Photodetectors with a Resonant Cavity for Near-Infrared Polarimetric Detection

“…Especially, there is still a long way to go before polarimetric detection is realized by the PDs in III-Vs and II-VIs. Being the major material of the semiconductor industry, silicon has emerged as optoelectronic devices in recent years due to their distinct optical and electrical properties [6–8], well-established process, and high compatibility with the developed CMOS technology [9]. Furthermore, recent achievements in silicon photonics [10, 11] offer a promising pathway to realize the novel form of PDs by integrating Si nanowire detectors [12, 13] with photonic structures for new application such as polarimetric detection.…”